Becker-Scarpitta Antoine, Auberson-Lavoie Diane, Aussenac Raphael, Vellend Mark
Département de Biologie, Faculté des Sciences Université de Sherbrooke Sherbrooke Québec Canada.
Spatial Foodweb Ecology Group, Faculty of Agriculture and Forestry, Department of Agricultural Sciences University of Helsinki Helsinki Finland.
Ecol Evol. 2022 Aug 22;12(8):e9102. doi: 10.1002/ece3.9102. eCollection 2022 Aug.
Despite many studies showing biodiversity responses to warming, the generality of such responses across taxonomic groups remains unclear. Very few studies have tested for evidence of bryophyte community responses to warming, even though bryophytes are major contributors to diversity and functioning in many ecosystems. Here, we report an empirical study comparing long-term change in bryophyte and vascular plant communities in two sites with contrasting long-term warming trends, using "legacy" botanical records as a baseline for comparison with contemporary resurveys. We hypothesized that ecological changes would be greater in sites with a stronger warming trend and that vascular plant communities, with narrower climatic niches, would be more sensitive than bryophyte communities to climate warming. For each taxonomic group in each site, we quantified the magnitude of changes in species' distributions along the elevation gradient, species richness, and community composition. We found contrasted temporal changes in bryophyte vs. vascular plant communities, which only partially supported the warming hypothesis. In the area with a stronger warming trend, we found a significant increase in local diversity and dissimilarity (β-diversity) for vascular plants, but not for bryophytes. Presence-absence data did not provide sufficient power to detect elevational shifts in species distributions. The patterns observed for bryophytes are in accordance with recent literature showing that local diversity can remain unchanged despite strong changes in composition. Regardless of whether one taxon is systematically more or less sensitive to environmental change than another, our results suggest that vascular plants cannot be used as a surrogate for bryophytes in terms of predicting the nature and magnitude of responses to warming. Thus, to assess overall biodiversity responses to global change, abundance data from different taxonomic groups and different community properties need to be synthesized.
尽管许多研究表明生物多样性对气候变暖有响应，但此类响应在不同分类群中的普遍性仍不明确。很少有研究测试苔藓植物群落对气候变暖的响应证据，尽管苔藓植物是许多生态系统中多样性和功能的主要贡献者。在这里，我们报告一项实证研究，比较了两个具有不同长期变暖趋势的地点苔藓植物和维管植物群落的长期变化，使用“遗留”植物记录作为与当代重新调查进行比较的基线。我们假设，在变暖趋势更强的地点，生态变化会更大，并且具有较窄气候生态位的维管植物群落比苔藓植物群落对气候变暖更敏感。对于每个地点的每个分类群，我们量化了物种沿海拔梯度分布、物种丰富度和群落组成的变化幅度。我们发现苔藓植物和维管植物群落的时间变化形成对比，这仅部分支持了变暖假说。在变暖趋势更强的地区，我们发现维管植物的局部多样性和差异（β多样性）显著增加，但苔藓植物没有。存在-缺失数据没有提供足够的能力来检测物种分布的海拔变化。观察到的苔藓植物模式与最近的文献一致，文献表明，尽管组成发生了强烈变化，但局部多样性可能保持不变。无论一个分类群在系统上对环境变化的敏感程度是高于还是低于另一个分类群，我们的结果表明，在预测对变暖的响应性质和幅度方面，维管植物不能用作苔藓植物的替代物。因此，为了评估生物多样性对全球变化的总体响应，需要综合来自不同分类群和不同群落特征的丰度数据。
